Pivoted breech closure and lock member



April 1, 1952 H. LlPPEfiT ETAL 2,590,981

.PIVOTED BREECH cppsumz AND LOCK MEMBER Filed June 16, 1948 321 I 30 25 2/ ig Patented Apr. 1, 1952 UNITED" STATES PATENT OFFICE PIVOTED BREECH CLOSURE AND LOCK MEMBER Hanns Lippert and Erwin Hepperle, Zurich, Switzerland, assignors to Machine Tool Works Oerlikon,

Administration Company,

Zurich- Oerlikon, Switzerland, a Swiss company Application June 16, 1948, Serial No. 33,356 In Switzerland June 20, 1947 tainty of scoring hits and thus the probability. of

shooting down the attacking aircraft. With the same objective in view larger calibres, hitherto used as non-automatic weapons, are now being automatized. There have hitherto been technical limits to any increase in the rate of fire on the one hand and to the automatization of guns of larger calibre, for instance 75 mm. and more, on the other. necessary for locking the cartridge cannot exceed a certain value. But the breech blocks of guns of the size category of the calibres. mentioned are very heavy, so that in the rhythm of feeding the cartridges they can only move relatively slowly.

t would seem, however, hardly possible to overcome the difiiculties set out above by means of the breech systems so far known. The present invention relates therefore to an entirely new method and discloses an automatic weapon whose breech system is constructed in an entirely new manner. The new breech system, as will be shown hereunder, eliminates all the difiiculties enumerated above and makes it possible in firearms manufacture to automatize the heaviest calibres and to raise the rate of fire to the highest figures conceivable.

The automatic firearm in accordance with the present invention is characterized by at least one bolt bearing against the casing of the firearm and mounted pivotally in such fashion that, in order to absorb the forces generated by gas pressure, it engages immediately behind a projecting cap provided on the cartridge case.

The invention thus departs from the usual principle in fire arm manufacture whereby a breech block is provided which at the same time takes care of the forward feed of the cartridges and must therefore travel a relatively large distance. housing are now provided, which are pivotable into a position behind a projecting cap provided on the cartridge case and are therefore not called upon to perform any reciprocal motion. breech block hitherto customary merely retains, therefore, the function of a cartridge slide. and can therefore be constructed so as to be extremely light, taking for instance the form of a sheetmetal sleeve. By this means the masses The weight of the breech block The requiring to be accelerated, which as is known are the cause of the relatively low limit to the rate of fire of automatic firearms of larger calibre, are reduced to a minimum.

A particularly advantageous construction is achieved when at least two bolts, bearing against the firearm casing and capable of being pivoted behind a conical projection provided on the cartridge case, are provided, which are brought into the cartridge-locking position-by a power accumulator placed under tension by the cartridge slide in its forward course. A breech system of Only bolts bearing against the weapon this kind is, as will be shown, extremely simple in its construction and sets no limits either to the calibre or to the rate of fire, at least from a constructional point of view.

In the enclosed drawing, Figs. 1 to 5 illustrate a typical embodiment of the invention, in

which: N

Fig. 1 is a section through an automatic firearm, drawn diagrammatically;

Fig. 2 is an enlarged section through the locking mechanism during the insertion of a cartridge;

Fig. 3 shows the subject of Fig. 2 in the position in which the cartridge is locked;

Fig. 4 is a section along the line II in Fig. 3;

Fig. 5 is an elevation of a cartridge-case especially designed for use in the firearm illustrated.

In Fig. 1, I is the barrel, which is inserted in the firearm casing 3 in the known manner by means of a bayonet joint 2. .The reciprocally moving cartridge slide 4 is acted upon by a recuperating spring 5 andis provided in its fore portion with the percussion mechanism 6, as seen in Figs. 2 and 3. The two bolts I and 8 are mounted in bowl-shaped recesses 9 and I ll in the {firearm casing 3. The bolts 1 and 8 are operated by power accumulators, consisting of the rear portions II and I2 and the fore portions I3 and I4. The two power accumulators are operatively connected through the springs I5 and I6. The rear accumulator portions II and I2 are of forked shape and guided along the fore portions I3 and I4 of the accumulators. By

means of projections I1 and I8 they engage below the noses I9 and 2B of the bolts I and 8. The fore portions I3 and It of the accumulators are provided with bosses AI and 22 which engage,

the unlocked position, in corresponding recesses 23 and 24 in the bolts 1 and 8. In the locked position, on the other hand,- they come to lie on the surfaces 25 and 25 of the bolts I and 8, thus acting as wedges. The rear portions II and I? of the accumulator project into the path of has been fired, an opening force is exerted on the bolts. The fore parts l3 and I4 of the aceumulators are connected to rods 32 and 33 which, as shown in Fig. 1, carry pistons 34 and 35. The pistons 34 and 35 slide in cylinders 36 and 31, into which open the gas ducts 38 and 39 communicating with the barrel. Under the action of the gas pressure forces the pistons 34 and 35 and the rods 32 and 33 are accordingly-moved rearwards, this resulting in'a corresponding motion on the part of the fore portions l3 and M of the accumulators.

Finally, plates 40 and M, capable of being slidingly inserted inthe firearm casing, are provided, which form a seal when the bolts and the accumulators have been inserted.

The manner in which the automatic firearm illustrated functions is as follows: The cartridge slide 4 feeds, at each cycle, a cartridge into the cartridge chamber and in the course of that operation, shortly before the cartridge has been completely inserted into the chamber, strikes with its noses 21 against the rear portions II and 12 of the accumulators. In

consequence, therefore, there will first be produced a tensioning of the springs l5 and [3 until the rear portions II and I2 of the accumulators contact the fore portions l3 and .14 of the ac cumulators.

Meanwhile the cartridge has been inserted so far that its conical cap 29 no longer lies between the bolts 1 and 8. The projections l1 and I8 will now, through the forwardv motion of the rear portions H and. I2 of the accumulators, also release the noses I9 and 20 of the bolts 1 and 8, so that, as soon as the rear portions H and I2 of the accumulators strike hard against the fore portions l3 and M of the accumulators, the inwardly pivoting motion of-the bolts 1 and 8 is initiated by the bosses-2| and 22 of the fore portions I3 and M of the accumulators The bolts are pivoted into the position shown in Fig. 3, in which they engage behind the cap 29 of the cartridges, the accumulator springs l5 and I6 being thereb detensioned, these spring also causing the bosses 2| and 22 to take up a position below the surfaces 25".and 26 of the bolts 1 and 8, thus wedging the two bolts 7 and 8. r

In the position shown in Fig. 3 the cartridge islocked and the striking mechanism 6, which is operated in a manner known to those expert in the art and therefore not. here represented in greater detail, can perform its function. The bolts 1 and 8 absorb the gas pressure forces exerted on the cartridge when the round is fired, theunlocking process being however initiated, in themanner described hereunder, as soon as the round has been fired. v

The gases extracted from'the barrel through the ducts 38 and 39 force the \pistons 34 and 35 in the cylinders 36 and 3? towards the rear, whereby the fore portions l3 and M are likewise forced rearwardly through the rods 32 and 33.

The springs l5 and i6 are thereby again placed under tension and the bosses 2| and 22 withdrawn from the position in which they wedge the bolts land 8. Since, ashas been mentioned, the' conical surfaces 30 and 3|, by which the bolts bear on the conical cap 29 of the cartridge 28, are so designed that when gas pressure forces act on the cartridge case a force tending towards opening is exerted on them, the bolts are pivoted outwardly. The cartridge slide 4, also forced back under the action of the remaining gas pressure forces, now also releases the rear portions II and I2 of the accumulators, so that these, under the action of the springs l5 and [6, are likewise enabled to resume their initial position as shown in Fig. 2, the projections I! and I8 engaging above the noses l9 and 20 of the bolts 1 and 8 and thus securing the bolts. Thereby the initial position shown in Fig. 2 is reached, and a new cartridge can be ins-erted after the first cartridge has been ejected.

It should be added that the ejection of the cartridge can take place, for instance, in a downward direction (cf. Fig. 4).

The embodiment shown is, it need hardly be said, only a typical example of a manner in which the invention, which is new in principle, can be performed. Numerous further alternative em-' bodiments of the principle in accordance with the invention could be adduced.

. We claim:

1. In an automatic firearm, in combination with a percussion mechanism for inserting a cartridge case into a firing position, two swingable bolts located on opposite sides of said percussion mechanism and two movable accumulators hav ing bosses engaging said bolts and swinging them inwardly from an unlocked position to a locking position, and vice versa, said bolts engaging said percussion mechanism and the rear end of the cartridge case in said locking position, said accumulators having rearwardly directed projections and said bolts having noses engaging behind, said projections in the unlocked position of said bolts. I

2. In an automatic firearm, in combination with'a percussion mechanism for inserting a cartridge case into a firing position, said percussion mechanism including a cartridge slide, said cartridge case having a rear conical projection, two swingable bolts located on opposite sides of said percussion mechanism, two movable accumulators having bosses engaging said bolts, and springs engaging said accumulators, said cartridge slide engaging said accumulators and moving them forwardly while tensionin said springs, said bc'isses of the accumulators swinging said bolts from an unlocked position to a locked position when said accumulators are moved forwardly, said bolts engaging said percussion mechanism and said rear conical projection of the cartridge case in said locking position, said accumulators having rearwardly directed projections and said bolts having noses engaging behind said projections in the unlocked position of said bolts.

3. In an automatic firearm, in combination with a percussion mechanism for insertin a cartridge case into a firing position, said cartridge case having a rear conical projection, two swingable bolts located on opposite sides of said per cussion mechanism, two movable accumulators having bosses engagin said bolts and swinging them inwardly from an unlocked position to a locking position and vice versa, said bolts having conical surfaces engaging said rear conical projection of the cartridge'case in said locking position, the angle of said conical surfaces of the bolts being selected so that an opening force is exerted on the'bolts \rhen'gas pressure after firing acts on said 'cartrid-g'e'case, said accumulators having rearwardly directed projections and said bolts having noses engaging behind said projections in the unlocked position of said bolts 4. In an automatic firearm, in combination with a percussion mechanism for insertin a cartridge case into a firing position, two swingable bolts located on opposite sides of said percussion mechanism, two movable accumulators, each of said accumulators having a fore portion and a rear portion, and separate springs interconnecting the fore and rear portions of each accumulator, the rear portion of each accumulator being forked and adapted to move relatively to its fore portion, the fore portions of said accumulators having bosses engaging said bolts and swinging them inwardly from an unlocked position to a locking position, and vice versa, said bolts engaging said percussion mechanism and the rear end of the cartridge case in said locking position, said fore portions having rearwardly directed projections and said bolts having noses engaging behind said projections in the unlocked position of said bolts.

5. In an automatic firearm, in combination with a percussion mechanism for inserting a cartridge case into a firing position, two swingable bolts located on opposite sides of said percussion mechanism, two movable accumulators, each of said accumulators having a fore portion and a rear portion, and separate springs interconnecting the fore and rear portions of each accumulator, the rear portion of each accumulator being forked and adapted to move relatively to its fore portion, the fore portions of said accumulators having bosses extending into recesses formed in said 35 bolts in an unlocked position of said bolts, said bosses moving out of said recesses and swinging said bolts into a locking position during a forward movement of said accumulators, said bolts engaging said percussion mechanism and the rear end of the cartridge case and said bosses wedging said bolts in said IOCking position, said fore portions having rearwardly directed projections and said bolts having noses engaging behind said projections in the unlocked position of said bolts.

6. In an automatic firearm, in combination with a percussion mechanism for inserting a cartridge case into a firing position, two swingable bolts located on op osite sides of said percussion mechanism, two movable accumulators, each of said accumulators having a fore portion and a rear portion, separate springs interconnecting the fore and rear portions of each accumulator, separate pistons connected to the fore portions of said accumulators, and means transmitting gas pressure after firing to said pistons to cause said pistons and said fore portions to move rearwardly, said fore portions having bosses engaging said bolts and swinging them inwardly from an unlocked position to a lockin position during a forward movement of said fore portions, said fore portions further having rearwardly directed projections and said bolts having noses engaging behind said projections in the unlocked position of said bolts.

HANNS LIPPERT. ERWIN HEPPERLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,387,460 Beets -c Aug. 16, 1921 FOREIGN PATENTS Number Country Date 785,581 France Mar. 26, 1934 

